Bluetooth configuration, can listen to music, answer the phone. Let speed match music and ride more happily. Helmet anti-fog lenses.The inner lens can be switched on and off at any time, preventing sunlight during the day and preventing car lights at night.The back of the helmet has a reflective material that is safer.Material: ABS,Suggested Size L(55-59)XL(60-62)XXL(62-64)CMThe top of the helmet has breathable holes at the front to ensure that the helmet is breathable and comfortable to open and close.